Fastener

ABSTRACT

A cam shaped prong on one part locks with a shouldered portion of another part by pressing one against the other. The parts are separated by an angular relative motion causing the prong to pivot and disengage. In one embodiment, the fastener is in the form of a removable cover as a protective device for temporarily blocking the socket of an electrical outlet. The cover is formed of a resilient, flexible material having a tab on one side and a pair of spaced prongs on the other side. The prongs are formed with facing shoulders which latch onto a socket when pressed therein. The prongs also are configured with cam surfaces which work against the edges of the socket to produce a spreading motion of the prongs when the cover is rotated whereby it may be released from the socket.

owerman 41 FASTENER [72] Inventor: William R. Bowerman, 2457 Jasu Dr.,Lawrence, Kans. 66044 [22] Filed: Dec. 21, 1970 [21] Appl. No.: 99,994

[52] US. Cl. ..339/38, 24/208 A, 24/73 P, 24/201 S, 24/221 R [51] Int.Cl. ..A44b 17/00 [58] Field of Search ..24/208 A, 73 P, 107, 201 S,24/204, 213, 208, 113, 73 PF, 73 S, 73 AP, 230 TC, 230 F, 230 SL;339/38, 36; 248/223;

[ 1 Aug. 22, 1972 3,387,252 6/1968 Rothweiler ..339/38 FOREIGN PATENTSOR APPLICATIONS 935,829 9/1963 Great Britain ..339/38 729,314 3/1966Canada ..339/38 Primary Examiner-Bemard A. Gelak Attorney-Morse, Altman& Oates ABSTRACT A cam shaped prong on one part locks with a shoulderedportion of another part by pressing one against the other. The parts areseparated by an angular relative motion causing the prong to pivot anddisengage. In one embodiment, the fastener is in the form of a removablecover as a protective device for temporarily blocking the socket of anelectrical outlet. The cover is formed of a resilient, flexible materialhaving a tab on one side and a pair of spaced prongs on the other side.The prongs are formed with facing shoulders which latch onto a socketwhen pressed therein. The prongs also are configured with cam surfaceswhich work against the edges of the socket to produce a spreading motionof the prongs when the cover is rotated whereby it may be released fromthe socket.

7 Claims, 17 Drawing Figures Patented Aug. 22, 1972 .2 Sheets-Sheet lM/VE/VTOR WILLIAM R. BOWERMAN B) 7%,, Ow, 105E:

ATTORNEYS Patented Aug. 22, 1972 3,686,616

.2 Sheets-Sheet 2 F/G. /Z

62 0 U F/G /3 58 WILLIAM R. BOWERMAN ATTORNEYS FASTENER BACKGROUND OFTHE INVENTION 1. Field of the Invention This invention relates generallyto fastening devices including locks and more particularly is directedtowards a new and improved fastener of simplified construction, designand operation.

2. Summary of the Prior Art A wide variety of safety devices have beendeveloped heretofore for use with electrical outlets designed to protectchildren against shocks or electrocution as the result of insertingmetal parts into a socket. Since many infants and children have beeninjured in this fashion, considerable effort has been directed towardsprotective devices which permit opening of a socket. by an adult but notby a child. Most devices of this nature have been relatively complicatedmechanical affairs employing such techniques as spring-loaded rotary orsliding plates which close the socket in one position and open thesocket in another position. Devices of this nature are relativelyexpensive and usually require the services of an electrician to install.Furthermore, the spring components frequently fail with the result thatthe effectiveness of the device is lost.

Accordingly, it is one object of this invention to provide a new andimproved general purpose fastener of simplified construction,particularly adapted for use as a safety cover for electrical outlets orfor other locking and fastening applications. A further object of thisinvention is to provide a low-cost safety cover for electrical outletswhich cover is easily installed and removed by an adult but difficult tooperate by a child.

SUMMARY OF THE INVENTION This invention features a fastening devicecomprising a first member having a hook-shaped cam engageable with ashouldered second member by pressing the parts together. The parts aredisengaged by a rotary motion of the parts whereby the cam portioncooperates with the shoulder portion to bias the cam out of lockingengagement. In one embodiment it is used with an electrical sockethaving a pair of spaced openings with shoulders formed in the walls ofthe socket and comprises a body portion of slightly flexible material,the body portion being formed on one side with a pair of spaced prongsdimensioned for insertion in the sockets. The prongs are provided withoppositely facing hooking portions having leading cam portions adaptedto spread the prongs apart when the device is inserted straight into asocket until the hooking portions snap onto the shoulders of the socket.The cam portions are extended along the prongs in a manner to cause aspreading motion of the prongs when the body is rotated so as to releasethe prongs from the socket shoulders.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of asafety cover made according to the invention,

FIG. 2 is another perspective view showing the opposite side of thedevice,

FIG. 3 is a view in front elevation of the safety cover,

FIG. 4 is a view in rear elevation thereof,

FIG. 5 is a view in side elevation thereof,

FIG. 6 is a cross-sectional view taken along the line 66 of FIG. 4,

FIG. 7 is a top plan view of the device,

FIG. 8 is a fragmentary perspective view showing an electrical outletwith one cover in position,

FIG. 9 shows a cover being inserted in an electrical socket,

FIG. 10 shows the cover in full locking position,

FIG. 11 shows the cover being removed from the socket by a twistingaction,

FIG. 12 is a top plan view of a modification of the invention,

FIG. 13 is a perspective view showing another modification of theinvention,

FIG. 14 is a detailed sectional view of the FIG. 13 embodiment,

FIG. 15 is a perspective view of the prong member,

FIG. 16 is a perspective view of a further modification of theinvention, and,

FIG. 17 is a perspective view of the FIG. 16 prong member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings there is illustrated a fastener made according to the inventionas embodied in a protective cover plate for an electrical outlet. Thedevice is generally organized about a circular body portion 10 of aslightly resilient, flexible and electrically insulating material suchas plastic or the like. The body portion, on its outer face, is providedwith an integral semi-circular tab 12 for gripping the device and on itsopposite face is provided with a pair of spaced prongs 14 and 16, alsointegral with the body portion.

The prongs l4 and 16 are spaced apart from one another in parallelopposition. Each of the prongs is formed with a relatively wide, baseportion 18 rising smoothly from a flat rear surface 20 defining the backface of the body 10. The base portion of the prongs, as viewed in sideelevation, extends to an apex 22 from the face 20 defining inwardlyprojecting hook or shoulder portion 32. The shoulder portion 32 extendstowards a similar shoulder portion on the opposite prong and the edgesthereof are faired smoothly into the curved edges 24 and 26 of theprongs. Thus in rear elevation, each shoulder portion 32 defines asmooth protuberance 34 defining a cam surface together with the edges 24and 26.

Referring now more particularly to FIGS. 8 through 11, there isillustrated the cover in conjunction with a socket 36 of an electricaloutlet generally indicated by the reference character 38. In a typicalsocket for an electrical outlet, a pair of spaced slots 40 and 42 areformed in a face plate 44 in register with electrically conductivecontacts 46 and 48 which normally receive the prongs from an electricalplug inserted in the socket. The face plate 44 includes a central webportion 50 having inwardly facing shoulders on either edge thereofadjacent the slot openings 40 and 42.

As shown in FIG. 9, when the device 10 is to be plugged into position,the prongs 14 and 16 are aligned with the slot openings 40 and 42 thedevice is pushed into the socket. The inward pressure causes the prongsto spread apart, bending the body portion 10 as shown in FIG. 9. Thespreading action is caused by the cam protuberances 34 of each prongriding over the outer edges of the central portion 50 until they snapinto locking engagement with the inner edges of the portion 50, as bestshown in FIG. 10. In this condition, the body portion overlays the outerpart of the socket, effectively closing it so that a child would beunable to injure himself by innocently inserting a metal instrument intothe socket. In this position the device cannot be pulled away from thesocket by virtue of the hook portions locking with the shoulders of theface plate.

The device can be removed only by twisting the device about its axis inthe manner shown in FIG. 11. This is done by grasping the tab 12 andturning the device in a clockwise or counterclockwise direction. Thetwisting of the device causes the curved edges 24 and 26 of the prongstogether with the cam portion 34 to produce a spreading action of theprongs. The cam surfaces of the prongs, under the turning action, rideagainst the socket edges, forcing the prongs apart to an extentsufficiently for the hook portions 32 to clear the central portion 50 ofthe face plate. Once the hook portions are clear of locking engagementwith the face plate and the body portion distorted in the manner shown,the device is easily withdrawn.

While the device is shown in use as a safety cover plate for anelectrical outlet, it could be used with equal advantage for otherfastening applications in which two parts are to be detachably connectedto one another.

Referring now to FIG. 12, there is shown a modification of the inventionand in this embodiment a body portion 10 is of rigid material whileprongs l4 and 16' are made up of two sections connected by a springloaded hinge 52. With this construction, the device need not be flexiblethe hinged prongs pivot on their hinges when the device is twisted in areceptacle.

In this embodiment of FIGS. 13 and 14 a single prong member 54 is usedwith a striker plate 56 in a lock system such as for an automobile door.The prong member is pivotally mounted to a yoke 58 and normally urgedclockwise as viewed in FIG. 14 by springs 60 to lock against the platewhen the prong member and plate are pushed together. The yoke 58 isfixed to a shaft 62 pivotally supported in bearing 64, the shaft beingoperated by a crank arm 66 engaging a shipping rod 68. Handles 70 and 72pivoted to a fixed frame engage each end of the rod 68 whereby the yokeand its member 54 may be rotated from either point to disengage themember from the plate, the prong member working against the edge of theplate as in the principal embodiment.

Referring now more particularly to FIGS. 16 and 17 there is illustrateda further modification of the invention and, in this embodiment, a prongmember 74 is rotatably mounted to an axially movable rod 76 slidablymounted to a fixed yoke 78. The member 74 is restrained against axialdisplacement with respect to the rod but is rotatably mounted theretobeing normally urged in a clockwise direction by springs 80. The springsserve to keep the prong member 74 engaged with a striker plate 82, applyopposing axial pressure to keep the prong member in the center of thestriker plate aperture and return the prong member 74 and its rod 76 toa center position after disengagement from the plate. Unlocking actioninvolves an axial displacement of the rod 76 together with the prongmember to the right in FIG. 16 which will cause the contoured prongmember, working against the striker plate, to

rotate ounter loc 'se and dise a e. nsofar th unlocking motion ifs i none direci n oniy one side 0 the prong member need be cam contoured asbest shown in FIG. 17.

Having thus described the invention what I claim and desire to obtain byLetters Patent of the United States is:

1. A fastener for engaging a member formed with a pair of sockets andshoulders recessed therein, comprising,

a. a body portion formed with at least one surface,

b. a pair of movable prongs extending outwardly from said body portionin a first direction perpendicular to said surface,

c. resilient means normally urging one of said prongs in a seconddirection perpendicular to said first direction,

. said one prong being formed with a substantially flat shouldersubstantially parallel to said surface and being along the portion onlyof said one prong that faces the other prong and adapted to engage theshoulder of said member,

e. said one prong being formed with an inclined leading face extendingfrom the apex thereof to the outer terminus of said prong shoulder andadapted to ride against said member during a locking motion in saidfirst direction whereby said one prong will be displaced in a directionopposite said second direction and then return in said second directionwhen said shoulders align,

f. said surface and said prong shoulder being spaced apart by a distancesubstantially corresponding to the depth of said member shoulder tolimit the locking motion therebetween,

g. said one prong being formed with sloping cam edges adjacent saidprong shoulder and said face in position to engage the edges of saidmember shoulder when said body portion is twisted about an axis parallelto said one direction to cause said one prong to move in said oppositedirection and disengage said shoulders.

2. A fastener according to claim 1 wherein said body portion includes apair of spaced oppositely facing matching prongs adapted to engage apair of similarly spaced sockets.

3. A fastener according to claim 2 wherein said fastener is formed of aresilient material.

4. A fastener according to claim 2 wherein said prongs are hinged tosaid body portion.

5. A fastener according to claim 2 including a tab extending from saidbody portion on the side opposite said prongs.

6. A fastener according to claim 2 wherein said body portion is acircular disc and said prongs are in spaced parallel relation on oneface thereof.

7. A fastener according to claim 1 wherein said one prong is pivoted tosaid body portion about a first axis, means mounting said body portionfor angular movement about a second axis normal to said first axis, andlinkage means connected to said body portion for an gular movementthereof.

1. A fastener for engaging a member formed with a pair of sockets andshoulders recessed therein, comprising, a. a body portion formed with atleast one surface, b. a pair of movable prongs extending outwardly fromsaid body portion in a first direction perpendicular to said surface, c.resilient means normally urging one of said prongs in a second directionperpeNdicular to said first direction, d. said one prong being formedwith a substantially flat shoulder substantially parallel to saidsurface and being along the portion only of said one prong that facesthe other prong and adapted to engage the shoulder of said member, e.said one prong being formed with an inclined leading face extending fromthe apex thereof to the outer terminus of said prong shoulder andadapted to ride against said member during a locking motion in saidfirst direction whereby said one prong will be displaced in a directionopposite said second direction and then return in said second directionwhen said shoulders align, f. said surface and said prong shoulder beingspaced apart by a distance substantially corresponding to the depth ofsaid member shoulder to limit the locking motion therebetween, g. saidone prong being formed with sloping cam edges adjacent said prongshoulder and said face in position to engage the edges of said membershoulder when said body portion is twisted about an axis parallel tosaid one direction to cause said one prong to move in said oppositedirection and disengage said shoulders.
 2. A fastener according to claim1 wherein said body portion includes a pair of spaced oppositely facingmatching prongs adapted to engage a pair of similarly spaced sockets. 3.A fastener according to claim 2 wherein said fastener is formed of aresilient material.
 4. A fastener according to claim 2 wherein saidprongs are hinged to said body portion.
 5. A fastener according to claim2 including a tab extending from said body portion on the side oppositesaid prongs.
 6. A fastener according to claim 2 wherein said bodyportion is a circular disc and said prongs are in spaced parallelrelation on one face thereof.
 7. A fastener according to claim 1 whereinsaid one prong is pivoted to said body portion about a first axis, meansmounting said body portion for angular movement about a second axisnormal to said first axis, and linkage means connected to said bodyportion for angular movement thereof.